Rhythmic patterns and synchronized states are commonly found in complex systems composed of a large number of interacting oscillatory elements. These patterns play a role for a number of biological functions such as cardiac rhythm [1], circadian rhythm [2], olfactory sensation [3], and cognitive processes such as memory and visual perception [4], among others. Conversely, malformed neurological/biological patterns have been linked to diseases such as epilepsy [4], PD-related tremors [5], and cardiac fibrillation [6]. In each of these cases, the emergent behavior of the population is a result of the interactions among individual elements. Early attempts to control the behavior of these oscillatory systems have focused on simply overwhelming the delicate coupling between elements with large external perturbations. Unfortunately, this has the adverse effect of suppressing (or distorting) the natural oscillatory rhythms that comprise the original system. The present invention relates a device and methodology by which a mild perturbation signal can be tailor engineered to produce a desired emergent behavior within a physical or biological oscillatory system. The construction of the signal utilizes the fundamental dynamics which govern oscillatory populations to gently steer the system to the desired state, rather than forcibly driving the system in an un-natural way. The weak nature of the feedback preserves the underlying oscillatory behavior, while controlling the overall emergent behavior of the population. Immediate applications of this methodology include, but are not limited to, the treatment of PD-related tremors, essential tremors, and epileptic seizures.